Folding tripod construction



Feb. 9, 1954 B. H. DALTON FOLDING TRIPOD CONSTRUCTION 2 Sheets-Sheet 1 Filed Aug. 22. 1949 EPUCZ' 0144 70/) IN VEN TOR.

Feb. 9, 1954 B. H. DALTON 2 Sheets-Sheet 2 Patented Feb. 9, 1954 FOLDING TRIPOD CONSTRUCTION Bruce H. Dalton, Los Angeles, Calif., assignor, by

mesne assignments, to Houston-Fearless Corporation, a corporation of California Application August 22, 1949, Serial No. 111,593

15 Claims. (01. 248-169) My invention relates: generally to supports for motion picture cameras, television cameras, directional antennas, optical instruments, and the like; Moreparticularly, my invention relates to a folding tripod especially suited for use with television cameras.

A camera tripod, especially suited for the purpose last above mentioned, should preferably be of such; construction as to be light enough to be readily portable, yet must be a substantially motionless, vibrationless base for the camera. It is also highly desirable that the tripod be foldable" so that it may be quickly and easily transported. from one place to another.

Stillfurther, the construction should be such that the operator may quickly adjust the same to suit various conditions of use, without the necessity of a large number of small catches, latches, or thumb screws.

Bearing in mind the general desiderata above mentioned, it is one object ofmy invention to provide a tripod of. the class above described'oi light and rigid construction and having adjustable feet by which the device may be adapted for use either on a flat interior floor such as a hardwoodor marble floor", or alternatively, can be adjusted" for'use on rough ground.

It is another object of my invention to providea i'oot'construction for tripods which incorporatesa universal joint, thus allowing the foot. to accommodate itself to different angular adjustments of the tripod or uneven ground.

A further objector theinvention is to provide in an adjustable: foot of the nature above stated means to present either a flat support surface for: use-0n floors, or a retractable spur'which may'bethrust into the ground when'the tripod isused out-of-doors.

An additional object of" the invention is to provide a linkage system for rigidly interconnecting the three: legs of a tripod when the same is in anexpanded position'for use.

A still further object of the invention is to prov-idea latch mechanism forsimultaneously latching'the tripod legsin'a' closed position when the device is" folded for transportation.

Still another object is to provide a tripod construction in. which the under side of thehead is; readilyaccessible for the purpose of attaching or detaching tilt heads and other objects on the top of the tripod,

The foregoing and-additional objects and advantagesoffthe inventionwill be apparent from consideration of the-following detailed descriptie -thereof; suchv consideration being giverrlikawi'sate-"the attaohed drawings; which;

Figure 1 is a perspective view of the tripod in unfolded position ready for use and with the feet adjusted for use in rough ground;

Figure 2 is an elevational partially sectioned fragmentary view taken in the plane of one of the legs and with the tripod shown in folded condition ready for transportation;

Figure 3 is an elevational section taken on the line t-3 in Figure 2;

Figure 4 is a horizontal section taken on the line ll in Figure 2;

Figure 5 is a horizontal section taken through one leg along the line 55 in Figure 2;

Figure 6 is a horizontal section taken through one leg-on the line $6 in Figure 2;

Figure '7 is a partial front elevational view of one of the tripod feet adjusted to a condition for interior use; and

Figure 8 is a side elevational view of the portion shown in Figure '7.

Referring first to Figure 1, it will be seen that the tripod embodying this invention includes three leg assemblies, indicated generally by the reference character 15, the leg assemblies being hingedly secured at their upper ends to a common central body It and each having a foot assembly ll at the lower end. The leg assemblies I5 are additionally supported by three divergent struts [8, each pivotally secured at an outer end to one of the leg structures, and at the inner end to a central clamp member it which is vertically slidable on a central post 20. The central post 20' is, in turn, supported in the body it on a downardly projecting spider portion 2|, the nature and purpose of which will be described in more detail hereinafter.

The'struts [8 are shown in a substantially horizontal position in. Figure l, but may assume a more or less inclined position depending on the adjusted, position of the clamp l9 alon the central postzfl. The struts It being of a fixed length, adjustment of the clamp member l9 upwardly or downwardly along the post 26 draws the leg assemblies l-5' inwardly or projects them outward- 1y soas to converge-or diverge the legs to change the relative spread of the. three assemblies. A clamp,.havin-g a fluted hand knob 22, is provided for the purpose of securing the clamp member l9' at any desired position along the post 20. The interconnection of the leg assemblies in the manner just described coordinates the movement of the leg assemblies so that. they assume, at all times, an equal. angular disposition with respect to thecenter post 20.

A tilt head 25', indicated. in phantom line in Figure I, and inlFigure 3, is shown secured to 3 the top of the central body I6. Such a tilt head or other similar mechanism may be secured to a horizontal platform portion of the tripod body by means of a relatively large hand nut 26 located underneath the top of the body as shown in Figure 3. Each piece of equipment intended to be secured to the top of the body I6 is provided with a downwardly projecting, exteriorly threaded boss 27 which projects through an aperture 28 in the platform and receives the hand nut 26. Such apparatus rests on a peripheral seat 29 at the top surface of the body I6, and an insert 30 having a keyway 3| therein is secured at a predetermined point in the seat 29 in order to uniformly align any equipment secured to the tripod, such equipment having an appropriately positioned key in the base thereof.

Having described the principal components of the tripod, the individual assemblies will now be described. For a discussion of the leg assemblies I 5, particular reference should now be made to Figures 2 and 3.

Each of the leg assemblies I comprises an inverted A-frame casting 35, and a tubular leg 40 clamped at the lower end of the A-frame 35. The upper ends of the A-frames straddle an elongated cylindrical boss 36 projecting from the body It. A through-rod 31 having an acorn nut 38 threaded to each end provides the pivotal connection between the A-frame 35 and the body I6. Thus, it is seen that the legs swing inwardly or outwardly in three mutually intersecting planes disposed at 120 to each other.

Each leg 40 is slidably supported for telescoping movement in the lower end of the A-frame 35, a tubular bore 4| being provided in the lower end of the latter member, the diameter of such bore being slightly larger than the external diameter of the leg 40. Adjacent the upper and lower ends of the bore II are formed counterbored recesses 42, each of which receives a split bearing ring 43, the dimension of the latter being such as to provide a relatively close sliding fit with the leg 40. Thus, the A-frame 35 may be cast of a relatively light material such as aluminum or magnesium, while the wear and corrosion resistance necessary to effect a fine slidin fit is provided by reason of the bearing ring 43.

In adjusting the tripod for use, the leg assemblies I5 are first spread apart and the legs 40 are then extended in telescope fashion to provide the desired height of the tripod. In many instances, it is desired to use the tripod in vertical position on a level surface in which case each of the legs 40 should be extended by the same amount. To this end, a numerical scale comprising engraved or printed numbers 45 is provided on each of the legs 49. An index window through which the scale numbers 45 may be read is formed in the A-frame 35 adjacent the bore M, as indicated by the reference character 46.

In order that the scale numbers 45 will always be positioned under the window and further, for proper operation of the foot assemblies IT, as will be hereinafter described, it is necessary that the legs 40 be prevented from rotating in the bore 4| while still being freely slidable therein. To this end, each of the legs 40 is formed with a longitudinal fiat 41 along the rear surface thereof, and a fiat disc-shaped key 48 is supported within the bore 4| in alignment with the flat 4? whereby to prevent rotation of the legs 40. The key 48 is positioned'in a small circular socket or seat 49 which is formed il 21.

4 interior of the bore M with a counterboring tool inserted through the index window 46.

When the legs 40 have been extended by the desired amount, they may be clamped in such position by means of a clamp rod 55 extending transversely across the lower end of the A-frame 35 and partially intersecting the bore 4I. The clamp rod 55 is exteriorly threaded at one end as indicated by the reference character 56 in Figure 2, and a fluted hand knob 51 is threaded onto the end of the rod 55. The rod 55 has an arcuate portion thereof cut away intermediate the ends thereof, which arcuate portion partially embraces the leg 40 so that when the hand knob 51 is tightened on the rod 55, the latter is moved axially to bind and clamp the leg 40 in its then position.

Turning now to a discussion of the means for bracin the leg assemblies I5 in any position thereof, and also to means for locking the leg assemblies I5 in a folded position, reference is made particularly to Figure 3. The center post 20 is secured at its upper end in the spider 2| in a closely fitting bore or socket 60 formed in the lower end of the latter, and a pair of drive pins 6| are inserted to further secure the center post 2! in place. The clamping member I9 is provided with a clamp rod 62 similar in nature to the leg clamp rod 55, one end of the clamp rod 62 carrying the hand knob 22.

The clamping member I9 is formed with three clevis-like projections 63 (see Figure 4), each of which receives an end of one of the struts I8 for pivotal connection thereto. A similar clevis-like projection 64 is formed at the lower end of each A-frame 35 adjacent the inner side thereof whereby to attach the outer end of each strut I8 to one of the leg assemblies I5.

As has been previously stated, the spread of the leg assemblies I5 depends on the position of the clamp member I9 along the rod 20. When this clamp member is located as shown in Figure 3, i. e., at its uppermost position along the rod 20, the struts I8 assume a position substantially parallel to the leg assemblies I5, the latter being then in completely folded position ready for transportation.

It is desirable that the legs be retained in such folded position during transportation, and to this end, a lock structure, indicated generally by the reference character I0, is mounted on the lower end of the center post 20. The lock assembly I0 includes a stud II pressed and brazed into the lower end of the center post 20 (the latter being of tubular construction), a lock ring I2 slidably carried on the stud II and retained thereon by a snap ring I3, and a compression spring I4 surrounding the stud II and contained within the lock ring I2. The compression spring I4 is an chored at its upper end against a shoulder I5 formed on the stud II, and at its lower end against an internal shoulder I6 in the lock ring I2. Thus, the lock ring I2 is normally thrust downwardly against the retaining ring I3.

Adjacent the upper end of the lock ring I2 is formed an annular, downwardly facing recess 11, the purpose of which is to catch and retain the heads of three latch bolts I8, one of which is secured in each of the struts I8 and has a tapered head I9 positioned and adapted to enter the recess II. It will be seen that, by reason of the sloping forward surface on the bolt head I9, the latter when moved inwardly toward the latch ring I2 engages the same and moves it upwardly against the urging of the compression spring I4.

tri'pod' structure assumes a tilted position.

' Thereafitenwhen the bolt head'l fl passestherim of "the-annular recess l 'l, thelatch ring 12* is for" example, at a point just belowthe hinge of the strut 1-8 the bolts T8 may be connected directly' to the legs Ii, and-Will witha slight lengthening of the post- Zll; engage and be held" by the-rings T2 in exactly the same manner as above described;

Whenitis desired torelease the lockassembly W in order to unfoldthetripod, one has merely to press upwardly on the-ring 12, thus simultaneouslyreleasing the three bolts 78 and permitting the legs to be swung outwardly.

Turning now-' to a'description' of the foot assemblies H", reference should be had to Figures 2, 3'; 7 and 8. Each foot assembly comprises a-yoke casting 80, a spur member 81, a pad member'82, and a lock screw assembly-8'3.

A- yoke member 80 is mounted to the bottom end of each leg ill, being positioned therein by a cylindrical boss 85 received in the tubular leg and secured therein by two set screws 86" threaded int'oaplug 8-1 weldedor brazed into the interior of theleg 40:

The yoke member 80- isformedwith a pair of downwardly extended arms 88', between the lower ends of which the spurmem-ber 8 1 having a removable spur 91 ispivotally'mountedi' on a pivot 'rod9il for swinging movement in a pl stantially perpendicular to the plane of the-A- frame' 351 Thus, thespu-r member at may be swung about its pivot rod 90 selectively intothe position shown in Figure 3 in which the spur 9! projects downwardly to engage the ground surface; or into the position shown in Figure 8 wherein the spur is in a substantially retracted position and the pad member 82 engages the ground. or other supporting surface; The'pad member 82 is provided with a friction pad 95, cemented or otherwise secured to its bottom surface-to prevent the structure from-'slipping'when supported on a polished floor or other smooth surface.

In many instances, it is desirableto so'adjust the extension of the legs 4!! so that the entire In such cases, it is necessary that each of the pad members 82' have at least two degrees of pivotal freedom in order that it may remain in flat contact" with the supporting surface. Tb this end, the pad member'82; instead of being mounted directly" to the yoke member 80, is mounted to the-spun'member 8l' by a pivot rod St disposed substantially at right angles to the spur pivot rod 99. Thus; the pad" member 82- may swing in the-"same plane: as does the A-f'rame35 by reason of the-'spur-pivot pin 90, and may rock in a plane perpendicular thereto by reasonof the-pad pivot "pin 96.

It is a further necessity to the use of 'thespur 91: that the same be rigid with respect to the leg 40; otherwise a lateral force applied to the-tripod would cause the spur to: tiltabout the-pivot pin 90, thus making the support unstable. For this purpose, a lock} serewassembly "83 isproridedon of the-toot assemblies t1; Themes as sembly 8-3 comprises anveyebolt; mo, pivotallycarried -betweentwo arms; 88-of the-yoke-member 80, and aflutedvhand knob I01;- threaded onto. the bolt H10. Each'iofthez pad members 82and the pad 95 secured thereto is. notched; at its upper end sothat. the eye: bolts H10 may-- be rocked downwardly: into the notch. and the hand knob I 01" tightened so as.- to"v pull the pad member 82 intoti'ght engagement with a. pair at abutments W3 formed in. the, yoke member as may be best seen in Figure 8. When; the -pad issecured in this manner, thespur N formsa rigid extension ofthe leg'4,il:..

Among the advantages; of. the present construc- 1 tion is: that? various pi'ecesr of apparatus may be quickly attachedv orrdetached from thetop-of the body-f6". Such: ease of: operation is: provided by the fact: that the spider member 2] is formed with three"dovmwardiyconverging struts I05 integrallycastwiththe bod-y t6, and thespaces between the: struts 05 are suchv that. the operators hand may. be. completely inserted through one. of the -Afr.ames: 35 andbetween; the struts N15- to reach the. hand nut; 28..

when. the: tripod: described herein is used in windy" locations; on. shipboard, on. the tops of moving-vehicles; aircraft, orwin other places Whereiitis liable to: be: upset, it is desirable to positively secur the tripod to-the supporting surface. Eor; this purpose, severalfastening: means are. provided the presentstructure. Each of the yoke members 80, i-n'the. foot. assembly I1 is flangedpas indicated by the reference character I l 0,, andthe flange is" formed with slots. as, forexample, at Ill; whereby each foot. assembly I! may' be. secured to the supporting surfac by a strap or-other fastening means.

Simila-rmeans'forsecuring the assembly to a supporting; surface :is-provided at the lower end of the center post 20 in the form of a. tongue I 12, formed in the-lowerend of the stud H and having an-ropening llfir. therein to which a. rope-tie or other fastening means may be secured. Similar perforatedtongues. H 4 are formed in the, lateral bosses 3 6 1 While the form of the device shown. and described herein is: fully capable of achieving. the objects and providing the advantages hereinbef'orestated, itwill. be realized. by those skilled in. the art that itisv capable of some modification without departure from the spirit. of the. invention. For this reason,I do not meanto. be limited to the formshown and described but rather to the scope of theappendedclaims.

I claim:

1; In a support structure of the. class having a plurality of legsl-secured'together at theirupper ends, a footstructure for each of. said legs .comprising; amcmber having a. grou-nd engaging spur secured therein, saidmember being. pivotally secured to the. lower extremity of said: leg for swinging movement inthe verticalv plane. of said leg'between. retracted; and ground-engaging positions; and apadhaving a flat ground-engaging 'surface. =pivotally secured. to said. member for position..

2. In av supportstructure of the class having-a plurality of legssecu-red together at their upper ends-a foot structure for each. of said legs -comprising: a. member having: a: ground-enga in spur? secured; therein, said" member: being;- piv- 'otally secured to the lower extremity of said leg that one is always in retracted position when the other is in ground-engaging position; and means to lock said member rigidly to said legto prevent said swinging movement with said spur thereof in ground-engaging position.

3. In a tripod having'inclined legs secured together at the upper end thereof, a foot structure for each leg comprising: a first pivot mounted adjacent the lower end of said leg, said first pivot being substantially perpendicular to a vertical plane through said leg; a member having a ground-engaging spur therein and being mounted on said first pivot for swinging movement thereon to retract said spur or extend the same into ground-engaging position, said member having a second pivot mounted therein substantially perpendicular to said first pivot; and a pad having a flat ground-engaging surface mounted on said second pivot for limited lateral tilting movement 'with respect to said member, the relative position of said spur and pad being such that one is always in retracted position when the other is in a ground-engaging position.

4. The construction of claim 3 further char- I acterized by having means in said leg including a clamp member positioned and adapted to engage said pad to lock the same rigidly against said leg with said spur in ground-engaging position.

5. In a foldable support of the class having a central body and a plurality of legs hinged thereto at their upper ends for convergent and divergent swinging movement of the lower ends of said legs between extended and folded positions, locking means for said legs comprising in combination: a first latch member mounted on said body substantially on a vertical central axis thereof and spaced below the top thereof, said first latch member having an annular recess concentric with said axis whereby a member in said recess is constrained by the side walls thereof against movement outward of said axis; and a plurality of second latch members each positioned adjacent an inner side of, and connected to one of said legs, normally free of said first latch member when said legs are extended, and positioned to make common entry into said recess when said legs are folded to hold all of said legs in a folded position in which they are substantially mutually parallel.

6. In a foldable support of the class having a central body and a plurality of legs hinged thereto at their upper ends for convergent and divergent swinging movement of the lower ends of said legs between extended and folded positions,

locking means for said legs comprising in combination: a plurality of first latch members each connected to one of said legs and positioned adjacent an inner side thereof whereby to move toward each other when said legs converge; and a second single latch member movably mounted on said body, spaced below the top thereof and normally out of engagement with said first latch members when said legs are extended, said second latch member being aligned with the path of swinging movement of said first latch members 'whereby to make common engagement with all of said first latch members when said legs are folded to hold all of said legs in a folded position in which .they are substantially mutually tween said second latch member and body to urge said second latch member in an engaging direction and inclined surfaces on said first latch members positioned and adapted to make contact with said second latch member when said legs are folded inwardly whereby to move said second latch member against the urging of said spring to effect said locking engagement thereof.

8. In a foldable support of the class having a central body and a plurality of legs hinged thereto at their upper ends for convergent and divergent swinging movement of the lower ends between extended and folded positions, bracing and locking means comprising in combination: a plurality of struts having the inner ends thereof hingedly secured to a common member and an outer end of each hingedly secured to one of said legs for concurrent swinging movement of said legs and struts between a folded position in which said legs and struts are substantially parallel with said struts lying inside of said legs and an extended position in which said legs are inclined and said struts are substantially in a common horizontal plane; a first latch member mounted on said body substantially on a vertical central axis thereof and spaced at a substantiall fixed distance below the top thereof, said first latch member being independent of, and disconnected from said struts during the aforesaid swinging movement thereof; and a plurality of second latch members one fixed to each of said struts, free of said first latch member when said legs are extended, and positioned to make common engagement with said first latch member when said legs are folded to hold said struts and legs in said folded position, said first and second latch members being adapted for simultaneous relative movement with respect to each other to effect simultaneous release of said second members.

9. In a foldable support of the class having a central body and a plurality of legs hinged thereto at their upper ends for convergent and divergent swinging movement of the lower ends between extended and folded positions, bracing and locking means comprising in combination: a vertical central post secured to said body and extending downwardly therefrom; a member slidably mounted on said post for vertical adjustment-therealong; a plurality of struts having the inner ends thereof hingedly secured to said member and an outer end of each hingedly secured sition in which said legs and struts are substantially parallel and an extended position in which said legs are inclined and said struts are substantially in a common horizontal plane; clamp means mounted on said member to secure the same to said post in any adjusted position thereof whereby to secure said legs in their then inclined position; a first latch member mounted on said central post-adjacent the lower end thereof; and a-plurality of second latch members, each connected to one of said legs adjacent an inner side thereof and, free of said first latch member when said legs are extended, and positioned to make common engagement with said first-latch member when said legs are folded to hold said legs in said folded position, said first and second latch members being adapted for simultaneous relative movement with respect to each other to effect simultaneous release of said second members.

10. In a foldable support of the class having a central body and a plurality of legs hinged thereto at their upper ends for convergent and divergent swinging movement of the lower ends of said legs between extended and folded position, a leg assembly comprising in combination: an inverted A-shaped frame having an axial bore formed in the lower juncture end thereof and aligned transverse hinge bearings in the upper spaced ends thereof for connection to said body, said bore having a window cut through an outer wall thereof; a tubular leg slidably received in said bore for telescoping adjustment therein, said leg having a longitudinal fiat along one side thereof and a linear scale marked along the length thereof, said scale being positioned under said window whereby to be viewed therethrough; a fiat seat formed in the interior surface of said bore intermediate the ends thereof; a fiat key member in said seat aligned with said fiat to prevent rotation of said leg in said bore; clamp means in said bore to secure said leg in any adjusted position thereof; a plug-shaped member secured in the lower end of said leg and having a bifurcated extension with transvers pivot bearings formed therein, said pivot bearings being aligned on an axis parallel to said hinge bearings; a member having a ground-engaging spur therein and being mounted in said transverse pivot bearings for swinging movement to retract said spur or extend the same into ground-engaging position, said spur member having a second pivot mounted therein substantially perpendicular to said first pivot bearings; and a pad having a flat, ground-engaging surface mounted on said second pivot for limited lateral tilting movement with respect to said spur member, the relation of said spur and pad being such that one is always in retracted position when the other is in a ground-engaging position.

11. In a support structure of the class having a plurality of legs secured together at their upper ends, a foot structure for each of said legs comprising: a member having a ground engaging projection formed therein, said member being pivotally secured to the lower extremity of said leg for swinging movement in a vertical plane of said leg between retracted and ground engaging positions; and a pad having a flat ground engaging surface pivotally secured to said member for swinging movement in a plane intersecting said first plane, the relative positions of said projection and surface being such that one is always in retracted position when the other is in ground engaging position.

12. A foot structure for a tripod leg comprising in combination: a first member having a ground engaging projection and being adapted for connection to the lower end of a tripod leg for pivotal movement of said member about a first axis intersecting a plane through said leg; and a second member having a fiat ground engaging surface and being connected to said first member for pivotal movement about a second axis intersecting a plane through said first axis whereby to permit self adjustment of said surface to be horizontal when said leg is inclined, said projection and surface being relatively positioned to face in divergent directions from said first axis whereby said projection and surface may be selectively placed in ground engaging positions by swinging said first member about said first axis.

13. In a foldable support of the class having a central body and a plurality of legs hinged thereto at their upper ends for convergent and divergent swinging movement of the lower ends of said legs between extended and folded positions, locking means for said legs comprising in combination: a first latch member mounted on said body substantially on a vertical central axis thereof, spaced below the top thereof, and movable between latching and unlatching positions; a plurality of second latch members each connected to one of said legs and positioned adjacent an inner side thereof to make common engagement with said first latch member to hold all of said legs in a folded position in which they are substantially mutually parallel; and spring means connected between said body and first latch member to urge the latter toward said latching position thereof.

14. The construction of claim 13 further characterized in that said second latch members having inclined surfaces formed thereon to engage said first latch member as said legs are folded to move said first latch member against the urging of said spring as said legs are folded.

15. In a foldable structure of the class having a body, and a plurality of legs hinged thereto at their upper ends for convergent and divergent swinging movement of the lower ends of said legs between extended and folded positions, locking means for said legs comprising in combination: a vertical central post fixed to said body and extending downwardly therefrom; a first latch member mounted for limited latching movement on said post adjacent the lower end thereof, said first latch member being disconnected from said legs during the aforesaid swinging movement thereof; and a plurality of second latch member independent of each other and each connected to one of said legs and positioned adjacent an inner side thereof to make common engagement with said first latch member to hold all of said legs in a folded position in which they are substantially mutually parallel.

BRUCE H. DALTON.

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